REAUMUR, RENE ANTOINE FERCHAULT DE (1683-1757), French scientist, was born on Feb. 28, 1683, at La Rochelle, where he received his early education. In 1703 he came to Paris, where he continued the study of mathematics and physics, and in 1708 was elected a member of the Academie des Sciences. In 1710 he was charged with the official description of the useful arts and manufactures of France, which led him to many practical researches that resulted in the establishment of new manufactures and the revival of neglected industries. For discoveries regarding iron and steel he was awarded a pension of 12,000 livres; but he requested that the money should be secured to the Academie des Sciences for the furtherance of experiments on improved industrial processes. In 1735 family arrangements obliged him to accept the post of commander and intendant of the royal and military order of Saint-Louis; he discharged his duties with scrupulous attention, but declined the emolu ments. Reaumur died at La Bermondiere, Maine, on Oct. 17, 1757. He bequeathed his manuscripts, which filled 138 portfolios, and his natural history collections to the Academie des Sciences.
Reaumur's papers deal with nearly all branches of science. He
examined and reported on the auriferous rivers, the turquoise mines, the forests and the fossil beds of France. He devised the method of tinning iron that is still employed, and investigated the chemical differences between iron and steel. His book on this subject (1722) was translated into English and German. The thermometric scale by which he is now best remembered was constructed on the principle of taking the freezing-point of water as o°, and graduating the tube of the thermometer into degrees each of which was one-thousandth of the volume con tained by the bulb and tube up to the zero mark. It was an accident dependent on the co efficient of expansion of the par ticular quality of alcohol em ployed which made the boiling point of water 8o° C; and mer curial thermometers the stems of which are graduated into eighty equal parts between the freezing and boiling-points of water are Reaumur thermometers in name only. Reaumur wrote widely on natural history, his best known work on this subject being the Memoires pour servir l'histoire des insectes (6 vols.,